Interchangeable die sets



Nov. 6, 1962 Y J. J. STRNAD 3,062,083

INTERCHANGEABLE DIE SETS Filed May 20, 1958 4 Sheets-Sheet 1 IN VEN TOR. JAMES J. STRNAD BYCORBETT, MAHONEY, MILLER & RAMBO. ATT

Nov. 6, 1962 J. J. STRNAD 3,

INTERCHANGEABLE DIE SETS Filed May 20, 1958 4 Sheets-Sheet 2 IN VEN TOR. JAMES J. STRNAD W 20 BY Nov. 6, 1962 .1. J. STRNAD 3,062,083

INTERCHANGEABLE DIE SETS Filed May 20, 1958 4 Sheets-Sheet 3 Q Q- 82 a O--7| mm W m- LQ a ma 6?! INVEN TOR. JAMES J. STRNAD tats 3,062,083 INTERCHANGEABLE DIE SETS James J. Strnad, Bedford, ()hio, assignor to Lempco Products, Inc., Redford, Ohio, a corparation of Ohio Filed May 20, 1958, Ser. No. 736,579 6 Claims. (Cl. 83637) The present invention relates generally to die sets for machine presses, and more particularly to new and improved die sets which are standardized, so as to interchangeably receive and detachably mount a given set of punch and die members without necessitating expensive, time-consuming and laborious prealignment and attachment procedures heretofore necessary in the mounting of a set of punch and die members upon prior art die sets.

The use of die sets in machine presses for the purpose of maintaining precise and exacting alignment between co-operating punch and die members during stamping or punching operations is now practically universally accepted practice. However, in the use of prior art die sets comprising a pair of relatively reciprocal plate-like shoes united for relative reciprocation by means of a plurality of relatively telescoping pin and bushing members, the cooperative die and punch members are ordinarily permanently and securely mounted and fixed, in prealigned relation, to the relatively heavy plate-like shoe members of the die set, and when once mounted upon the shoes of the die set, thereafter form substantially an integral, nondetachable part thereof. In view of the relative size and weight of the shoe members of a die set, considerable difiiculty and expense is encountered in the storage and handling of the punch and die members and their associated die set shoes, and in the transportation of the die set and attached punch and die members from one operating location to another. Hence, for an operator having business establishments in different cities, it has become economically infeasible to ship or transport a given set of punch and die members and their attached die set shoes between several difierent locations. This, in many cases, has necessitated the duplication of a given set of punch and die members and their associated die set shoes, in order that each of several difierent operating locations might be equipped to produce a given stamping or other workpiece. Naturally, this duplication of punch and die members and the associated die set shoes represents a considerable expense to the press operators, and oftentimes reduces the overall productive capacity of such operations.

Accordingly, it is the primary object of the present invention to provide a new and improved die set which is capable of detachably receiving and mounting a given set of punch and die members in exact operating relation without resort to the expensive, time-consuming, and laborious prealignment and mounting procedures heretofore employed in permanently mounting and securing a set of punch and die members upon the shoes of a die set, thus making possible the interchange of a given set of punch and die members between duplicative die sets located, for example, in different cities. In this connection,'it will be understood that the present die sets are so formed and constructed as to permit the simple and facile detachable mounting of a given set of punch and die members upon the relatively reciprocal shoe members of the die set in accurately aligned operating relation to one another, while at the same time permitting the set of punch and die members to be easily removed and detached from the relatively heavy and large shoe members of the die set for storage and transportation between different operating locales.

Another object of the present invention is to provide a die set which is particularly adapted and constructed for the detachable mounting of so-called steel rule-type punch and/or die members which embody knife edgetype steel strips or segments mounted in and projecting outwardly from an associated, relatively lightweight punch or die-supporting block formed from plywood or the like, and which are employed in the high speed punching or stamping of sheet metal workpieces.

A further object of the present invention is to provide a die set of the aforesaid character which comprises a pair of relatively reciprocal shoe members adapted for mounting upon the relatively movable bed and platen members of a machine press, and united for extremely accurate reciprocating movement toward and from one another by means of suitable guide pin and bushing members, and wherein each of the relatively reciprocal shoe sections of the die set is provided with locating and attaching means disposed in predetermined fixed relation to the axes of the pin and bushing members, so as to detachably receive and mount upon the respective shoe sections of a die set a cooperative pair of punch and die-supporting blocks or plates in a manner to assure proper and accurate closing alignment between the punch and die members, thus enabling a single set of punch and die members and their associated relatively lightweight mounting blocks or plates to be interchanged readily between duplicative die sets.

Yet another object of this invention is to provide a die set for machine presses comprising relatively reciprocal, heavy duty shoe sections connected by relatively telescoping pin and bushing means, and wherein one of said shoe sections is provided with locating or indexing abutment surfaces disposed in predetermined or given spaced, angular relation to the axes of the pin and bushing means, and operable in association with relatively movable clamp means carried by such shoe section to receive and detachably mount thereon a punch or die-supporting plate or block formed from plywood or the like, in a manner to maintain the punch or die-supporting member in predeterrn-ined accurate operating alignment with an associated punch or die member detachably mounted upon the other shoe section in predetermined spaced, angular relation to the axes of the pin and bushing means.

Still another object of the invention is to provide a die set comprising relatively reciprocal shoe sections connected for reciprocating movement by means of relatively telescoping pin and bushing means, and wherein one "of the shoe sections includes a punch or die-supporting plate or member provided with accurately machined, relatively angularly related flat surfaces adapted for abutting engagement in at least three triangularly related lines-or points of contact with the outer concentric surfaces of the bushings of the pin and bushing means, so as to accurately and precisely locate such punch or die-supporting plate or member in a single given position with respect to the axes of the pin and bushing means.

For a further and more detailed understanding of the present invention and the additional objects and-advantages thereof, reference is made to the following description and the accompanying drawings, wherein:

FIG. 1 is a perspective view of a die set formed in accordance with the present invention showing the upper and lower shoe sections in assembled operating relation to one another;

FIG. 2 is a perspective view showing the upper'shoe section of the die set in inverted position as compared with FIG. 1;

FIG. 3 is a perspective view of the lower shoe section of the die set and its associated punch or die block mounted thereon;

FIG. 4 is a transverse vertical sectional view taken along the line 44 of FIG. 1 and showing the sectional details of the upper shoe section of the die set;

FIG. 5 is a detailed fragmentary vertical sectional view 3 taken along the line 55 of FIG. 1 and illustrating the relative location and relationship between the upper shoe section, its guide pin, the locating key or abutment member and the die or punch-supporting block member;

FIG. 6 is a similar view taken along the line 66 of FIG. 1 and showing the mounted relationship between the punch or die-supporting plate, a primary adapter plate, a riser block, and the associated lower shoe;

FIG. 7 is a plan view of the upper shoe section of a modified form of die set, looking toward the under side thereof;

FIG. 8 is a plan view of the lower shoe section of the modified form of die set shown in FIG. 7;

FIG. 9 is an enlarged detail fragmentary elevational view of the relatively stationary and movable clamping blocks employed in the modified die set shown in FIG. 7;

FIG. 10 is an enlarged fragmentary vertical sectional view taken along the line 1010 of FIG. 9 and showing particularly the return spring arrangement between the relatively stationary and movable clamping blocks employed in the die set disclosed in FIG. 7; and

FIG. 11 is a diagrammatic plan view illustrating the predetermined spaced and angular relationship between the pin and bushing members and the locating blocks and keys of the upper shoe section of the die set disclosed in FIGS. 16.

Referring now to the drawings, FIG. 1 illustrates in its entirety a die set formed in accordance with the present invention. This die set comprises a relatively thick, rectangular, plate-like upper shoe 15 which, in operation, is adapted to be secured to the movable platen or ram member of a press, not shown, by any suitable means, such as the upwardly extending, cylindrical stud-like shank 14. Alternatively, as will be understood, the upper shoe 15 may be secured to the movable member of the press, simply by bolting the shoe 15 to the movable member of the press in a conventional manner. The upper shoe 15 is formed toward its rearward or inner side with a pair of pin or post-receiving openings 16 in which are pressed fitted or otherwise suitably stationarily secured the upper end portions of a pair of downwardly extending guide pins or posts 17'. In the usual manner, the guide posts 17 extend a distance downwardly below the lower surface of the upper shoe 15 and are telescopically received within a cooperative pair of cylindrical tubular bushings 18 suitably secured, as by press fitting, within spaced openings 19 formed in a lower, plate-like shoe 20. Interposed between the outer surface of the pins or posts 17 and the inner walls of the bushings 18 are cylindrical tubular bearing retainers 21 which rotatably support therein a multiplicity of antifriction ball elements 22 of a diameter to extend radially inwardly and outwardly from the retainer 21 to rollingly engage the opposing surfaces of the posts 17 and bushings 18. In the usual manner, the antifriction ball bearings 22 are of the pre-loaded type with the diameters of the ball elements thereof very slightly exceeding the annular space provided between the outer surface of the posts 17 and the inner wall surfaces of the bushings 18. In this manner, the pins and bushings and bearing retainer serve to connect the upper and lower shoes 15 and respectively for accurately guided reciprocating movement, while at the same time eliminating any possibility of lateral play or deviation during reciprocating movement thereof.

The lower shoe 20 of the die set may, if desired, be secured directly to the bed of the associated press by means of bolting, or other fastening means, or, if desired, may be secured to the bed of the press in relatively elevated relation thereto through the use of a plurality of spacer or filler blocks 23 which are secured to the base of the shoe 20, along the outer side edges thereof, as by means of bolts or cap screws 24 which, if desired, may also be utilized in securing the =lower shoe 20 to the stationary bed or bolster of the press. It will here be understood that the use of the spacer or filler blocks 23 is optional depending upon the particular installation involved, and when so used, the blocks 23 serve to elevate the lower shoe 20 with respect to the associated bolster or bed of the press so as to provide accessible clearance space therebetween, and when desired, permit the guide bushings 13 to extend below the lower surface of the shoe 20 in controlling the shut height of the die set.

The parts of the die set previously enumerated, namely, the upper shoe, lower shoe, and pin and bushing means are common to present die sets, and as such, do not, per se, constitute the novelty of the present invention. In accordance with the present invention, the lower shoe member 20 is adapted to detachably receive and support thereon in a single given position, a punch or die-supporting means which, in the form of the present invention as disclosed in FIGS. 16 of the drawings, constitutes a pair of cooperative rectangular, flat plates 25 and 26. Advantageously, the lowermost of these plates 25 is comparatively heavier and thicker than the uppermost plate 26 in order to withstand and absorb the pressing forces encountered, while the uppermost plate 26- may be made of relatively thinner and less expensive metal stock which, if damaged, may be more readily and inexpensively replaced than the lower plate 25. However, for the purposes of the present invention, it should be understood that the die or punchsupporting means may take the form of a single integral plate member rather than a composite of the two separate plates 25 and 26- as shown in the drawings.

Mounted upon the upper plate 26, as by means of welding, bolting, or other appropriate fastening means, not shown, is a rectangular punch or die block 27 (see FIG. 3) which may comprise either the male or female member of cooperative punch and die means. Before attaching or securing the punch or die block 27 to the plate 26, the proper location of the latter relative to the plate 26 is predetermined by a trial and error closing of the upper and lower shoe sections of a master die set, in order that the punch or die block 27 is exactly located on the upper plate 26 relative to a pair of dowel-receiving openings 28 (see FIGS. 3 and 6) formed toward the outer side edges of the upper plate 26. In this regard, in order to insure against an improper location of the upper plate 26 upon the associated lower plate 25, the dowel-receiving openings 28 of the upper plate 26 and a pair of associated dowel pins 29, which are press fitted into the lower plate 25, are located at different distances relative to the edges of the plates 25' and 26, so that the dowelreceiving openings 28 of the upper plate will register with the dowel pins 29 only when the upper plate 26 occupies one given single position upon the plate 25, thus preventing accidental transposition of the upper plate 26 upon the lower plate 25. This is referred to in the art as foolproofing to make certain that in the assembly of the upper and lower plates, personnel will not accidentally reverse the positions of the plates which might otherwise occur due to the flush relation to the rectangular edges of the upper and lower plate members.

As will be understood, the dowel-receiving openings 28 and the dowel pins 29 are extremely accurately machined to provide proper alignment between the upper and lower plates and thereby eliminate substantially all tolerance between these members. After locating the upper plate 26 upon the lower plate 25 by means of the dowel pins 29 and openings 28, the upper plate 26 may be secured to the lower plate 25 through the use of flush-type cap screws or the like 30.

If desired, the lower plate 25 may be secured directly to the upper surface of the lower shoe 20 or alternatively, as indicated in the drawings, the lower plate 25 may be secured to a plurality of rectangular risers or spacer blocks 31 which are interposed between the lower surface of the lower plate 25 and the upper surface of the lower shoe '20. Preferably, the lower plate 25 is bolted, as at 32 (see FIG. 6), to the riser or spacer blocks 31, while, the riser blocks 3-1 may be bolted, in turn, to the lower shoe 20. Advantageously, in order to provide access to the bolts 32, the upper plate 26 may be formed with openings or slots 33 in registry with the bolts 32, so that the upper plate 26 and lower plate 25- may be detached as a unit from the riser blocks 31 and lower shoe 20.

In order to accurately locate the die or punch-supporting means in operative position upon the lower shoe 20, the lower or base plate 25 may be integrally formed, or otherwise suitably provided, with a pair of rearwardly extending locating or indexing bosses 34 and 35, as shown best in FIG. 3. The locating boss 34 terminates in a flat, planar abutment surface 36 disposed generally parallel to the rearward edge of the plate 25 and adapted to make diminished area contact with the outer cylindrical surface of one of the bushings 18. The other boss 35 is formed With a V-shaped notch 37 which defines on the boss a pair of spaced, angularly related, flat abutment surfaces 38 adapted to provide a diminished area of contact with two spaced points on the outer cylindrical surface of the other bushing 18. The spacing between the V-forming surface 38 of the boss 35 is such as to permit the outer cylindrical surface of the bushing 18 to partially enter the V-shaped notch 37 of the boss 35 whereby to prevent relative lateral displacement between the lower plate 25 and the bushings 18, while the flat surface 36 of the boss 34, forming the third angularly related point of contact with the other bushing 13, serves to locate the plate 25 relative to the axes of the bushings 18 in a manner to prevent radial shifting or displacement of the plate 25 in respect to the bushings 18. It should here be understood that the triangularly related flat abutment surfaces 36 and 38 of the bosses 34- and 35 are employed as a highly accurate means of locating the die supporting plates 25 and 26 at a predetermined single given position relative to the axes of the bushings 18 prior to the bolting or securement of the plates 25 and 26 to the lower shoe 20. Toward this end, in initia'lly assembling the plates 25 and 26 upon the lower shoe 20, the plates are slid or swung rearwardly toward the bushings 18 so as to insure firm abutting engagement between the flat surfaces 36 and 38 of the bosses and the outer surfaces of the bushings 18. When proper contact between these surfaces is insured, a leaf spring-type clamp 39 carried by the lower shoe 20, is tightened, by means of a cap screw 40 to apply holding pressure through an inturned lip 41 of the clamp 39 to the outer or forward edge of the lower plate 25, thus holding the same in tight abutment with the outer surfaces of the bushings 18. At this time, the plates 25 and 26 may be anchored securely to the lower shoe 2% or the riser or spacer blocks 31 as by means of the bolts 32. Thus it will be seen that the bosses 34 and 35 provide a positive and eflicient means for locating or indexing the punch or die-supporting plates 25 and 26 on the lower shoe member of the die set in a single given position relative to the axes of the pin and bushing mem bers which connect the upper and lower shoe sections of the die set. In this respect, the outer cylindrical surfaces of the bushings 13 are formed concentric with the axes of the pins and bushings to insure that the flat abutment surfaces 36 and 38 of the bosses of a given set of punch or die-supporting plates will be disposed in the same spaced and angular relation with respect to the axes of the pins and bushings of any number of duplicative die sets.

For locating or indexing the cooperative punch or diesupporting means on the upper shoe 15, the latter is formed a distance inwardly from the pins or posts 17 with an accurately machined keyway 42, as shown best in FIGS. 2 and 5, which receives and supports a locating key or abutment 43 of generally rectangular cross section and of a size to extend a distance downwardly below the under surface of the upper shoe 15. FIG. 2 of the drawings depicts the upper shoe section of the die set in inverted position, from which it will be noted that the locating key or abutment block 43 is secured in the keyway 42 and to the upper shoe 15 by means of cap screws or the like 44. Thus, the locating key or abutment block 43 extends generally transversely beneath the lower surface of the upper shoe 15, but terminates a slight distance inwardly from the outer side edges of the shoe so as to provide as much area of contact as is practicable with an associated die or punch-supporting block, hereinafter described. As will be understood, the locating key or abutment block 43 may be formed as an integral part of the shoe 15, or may, if desired, be formed as a separate part attached to the shoe, but in either case, the forwardly extending side surface of the locating key 43 is accurately machined to constitute a flat planar surface disposed in predetermined angular position with respect to a straight line joining the axes of the guide pins or posts 17.

By reference to FIG. 11, the line AB designates a straight line passing through the axes of the pins or posts 17, while the line C-D designates the plane of the outer surface of the key or abutment block 43. As will be hereinafter more fully explained, in order to accomplish standardization of the die sets to thereby provide interchangeability of a given set of punch and die-supporting members between different though duplicative die sets, the plane of the outer surface of the key or block 43 must be disposed at a given uniform distance from the line AB joining the axes of the posts 17, and in given, uniform angular relation thereto. In the form of the present invention disclosed herein, the angular relation between the line AB and the plane of the outer face of the key 43, indicated by the symbol alpha, is zero degrees, but, as will be understood, these two factors, namely distance, and angular relationship, may be varied as between different sizes or configurations of die sets, provided that for each size and configuration of die set, the distance X and the angle, alpha, must remain constant, in order to provide for interchangeability. Toward this end, it will be seen that the outer surface 43a of the locating key or block 43 must be machined or formed with precise accuracy so as to provide the desired distance and angular relationship between such outer surface and a line joining the axes of the guide pins or posts 17 of the die set.

Also, as a part of the punch or die-locating meansof the upper shoe section, there is provided a secondloeating block or flange member 45 which is secured along the left-hand side edge of the upper shoe 15, as viewed in FIG. 4 of the drawings, as by means of a plurality of cap screws 46. By reference to FIG, 4 of the drawings, it will be seen that the locating flange 45- is of a height to extend downwardly a distance below the bottom surface of the shoe 15, and terminates in a lower beveled edge 47. As in the case of the outer face 43a of the key 43, the inner side or face surface of the locating flange 45, and the associated side surface of the shoe 15 must be machined to a high degree of accuracy so as to locate the inner side surface 45a of the flange 45 at a predetermined exact distance Y (see FIG. 11) from a line E-F extending perpendicularly to the line A-B, and through the axis of one of the pins 17. So, also, the surface 451 of the locating flange 45 must always be disposed at a predetermined angle, theta, with respect to the line AB joining the axis of the posts 17, in order that all die sets of a given size and configuration may interchangeably receive a given set of punch and die-supporting members. In the form of die set disclosed in FIGS. 1 through 6, the angle theta is equal to ninety degrees, although it will be understood that this angle may be varied between different sizes and configurations of die sets, so long as the same is constant with all die sets of a given size or configuration. It should also be understood that while the drawings depict the locating flange 45 as a separate part from the shoe 15, the same may be formed as an integral part of the shoe if desired.

By reference to FIGS. 2 and 11, it will be seen that the inner side surfaces 43a and 45a provide an entrant, right angular corner to receive and accurately locate a rectangular punch or die-supporting block 48, preferably formed from plywood, and which is illustrated as supporting the depending knife edge segments 49 forming a generally rectangular die cooperative with the punch block 27 mounted upon the lower shoe section of the die set. In this regard, it will be understood that the block 48 may support either the male or female member of a given set of punch and die members or a combination of male and female members, with the lower plates 25 and 26 supporting the cooperative male or female members or combination thereof, depending upon the particular stamping or pressing operation to be performed thereby.

As will be seen by reference to FIGS. 4 and of the drawings, the steel rule or knife edge segments or strips 49 extend substantially through the associated plywood block 48 and terminate at their lower edges in beveled knife-edge extremities. The opposite or upper edges of the blade segments 4? terminate flush with the upper surface of the supporting plywood block 48 and in abutting engagement with a relatively thin, rectangular, metal backup plate 50. The back-up plate 50 is appropriately secured in position upon the upper shoe as by means of flush head screws or bolts 51. The back-up plate 50 serves to prevent wear upon the relatively expensive and heavy upper shoe 15 by absorbing impact forces imparted to the blade segments 49 during punching or pressing operations.

For the purpose of maintaining the punch or die-sup porting block 48 in tight-fitting accurate engagement with the locating key and flange 43 and 45 respectively, the upper shoe 15 is provided along its forward and righthand Side edges (as viewed in FIG. 1) with a pair of adjustable clamp plates or bars 52 and 53 respectively. As will be seen by reference to FIG. 4, the side clamp 53 is secured to the side edge of the upper shoe 15 by means of adjustable cap screws 54 which may be tightened to move the clamp 53 inwardly of the associated edge of the plywood block 48 so as to force the same into tight fitting engagement with the inner surface 45:: of the locating flange 45. In order to maintain the inner surface of the clamp 53 in flat, surface to surface, contact with the associated edge of the plywood block 48, the clamp 53 is provided with a plurality of screw threaded leveling screws 55 which extend through threaded openings formed in the clamp 53 and into abutting relation with the outer side edge of the upper shoe 15. As will be understood, by adjusting the leveling screws 55 during and following tightening of the cap screws 54, the clamp 53 may be maintained in parallel relation to the outer edge of the plywood block 48 and the outer edge of the upper shoe 15. This serves to prevent tilting or cocking of the clamp 53 and consequent application of non-uniform pressures to the side edges of the plywood block 48. The forward adjustable clamp 52 is secured to the forward edge of the shoe 15 in the same manner as is the side edge clamp 53, and is likewise provided with adjustable cap screws 56 and leveling screws 57.

Thus, in mounting the punch or die-supporting block 48 in connection with the upper shoe 15, the block 48 is positioned initially in abutting relation to the relatively fixed locating key 43 and flange 45 at which time the adjustable clamps 52 and 53 are tightened inwardly upon the opposite edges of the plywood block 48 to securely clamp the same in a desired single given position upon the upper shoe 15. In order to prevent accidental transposition of the upper punch or die-supporting block 48, due to its otherwise symmetrical configuration, one of the corners of the block 48 is beveled off as at 60, as shown in FIG. 2, and a foolproof pin 61, firmly carried by the upper shoe 15, projects downwardly into the entrant corner provided by the inner surfaces of the locat- 3 ing key and flange43 and 45 in a manner to prevent the full entrance of an unbeveled corner of the block 48 within the entrant corner provided by the locating members. In this manner, only the beveled corner portion 6% of the punch or die-supporting block 48 may be tightly received within the entrant corner provided between the locating members 43 and 45, thus eliminating the possibility of personnel reversing the position of the punch or die-supporting block 48 when installing the same in association with the upper shoe section.

Thus, it will be seen that through the provision of relatively fixed positions of the locating key 43 and the locating flange 45 with respect to the axes of the pin and bushing means, as between numerous different die sets of a given size and configuration, a given punch or die-supporting block may be interchanged between two or more duplicative die sets, and yet be maintained and secured in the same given single position on the upper shoe section of each die set. By the same token, due to the accurate location of the lower punch or die-supporting plates 25 and 26, afforded by the triangularly disposed flat surfaces of the bosses 34 and 35 against the outer concentric surfaces of the bushings 13, a given lower punch or die supporting plate structure may be interchanged between two or more duplicative die sets and the initial interfitting alignment between the male and female die and punch members will always be maintained without resort to individual trial and error alignment procedures upon each given interchange of a given set of punch and die members between duplicative die sets. This interchangeability, so far as the applicant is aware, has heretofore been impossible, due to the more or less fixed and permanent mounting of a given set of punch and die members on the shoe members of a die set.

FIGS. 7 through 10 illustrate a modified form of die set formed in accordance with the present invention and one which is employed for the support and guidance of relatively large-area punch and die-supporting members. Referring to FIG. 7, the numeral 70 designates a relatively large and heavy rectangular upper shoe which is provided a distance inwardly from each of the four corners thereof with depending guide posts or pins 71 arranged to telescope within cooperative bushings 72 carried upon a lower shoe 73, as shown in FIG. 8. The pin and bushing connections between the form of die set disclosed in FIGS. 7-10 and that disclosed in FIGS. 1-6 of the drawings are substantially identical in mechanical principle, but due to the relative size of the die set disclosed in FIGS. 7-10, it is necessary to utilize four rather than two pin and bushing guide assemblies between the upper and lower shoe components, in order to maintain the desired exact alignment of such components during relative reciprocation thereof. The upper shoe 70 is formed inwardly from one end thereof with a keyway 74 in which is received a pair of relatively spaced, longitudinally aligned, and accurately located and machined abutment keys 75 analogous in function to the single key 43 of the previously described form of the present invention disclosed in FIGS. 16 of the drawings. Along the rearward edge of the upper shoe 70, the latter is provided With three relatively spaced locating flanges or blocks 76 which are analogous to the locating flange 45. As in the case of the primary form of the invention, the locating keys 75 and locating flanges 76 provide an entrant corner to receive a beveled corner 70a of an associated die or punch-supporting plywood block 70b. The entrant corner provided between the keys 75 and flanges 76 is provided with a foolproof pin 61a cooperative with the beveled corner of the plywood block to prevent accidental transposition of the block on the upper shoe.

Disposed in opposing relation to the relatively stationary locating flanges 76 and adjustably secured to the opposite or forward edge of the upper shoe 70 are three adjustable clamps 77 which, as in the case of the clamps 53, are adjustable inwardly and outwardly with respect 9. to the relatively fixed flanges 76 so as to clamp the die or punch-supporting block 70b therebetween.

Disposed in opposing relation to the stationary locating keys 75 are two sets of movable clamp members generally designated at 78. Each set of the clamp members 7 8 comprises a stationary bar or block 79 secured within a recess or keyway 80 formed in the under surface of the shoe 70. The relatively stationary bars 79 are connected with the upper shoe 70 by means of appropriate fastening devices, such as the cap screws 81. Mounted adjacent the relatively stationary bars 79 are the cooperative movable clamp bars 82 which are secured to the upper shoe 70 for limited sliding movement by means of an elongated slot and pin connection as shown at 83. Connected between the stationary bars 79 and the movable clamp bars 82 are a plurality of contractile springs 84 arranged to urge the movable clamp bar 82 toward the relatively stationary bar 79. The ends of the springs are connected with the bars 79 and 82 by means of removable pins 84a. Opposing the action of the springs 84 are a plurality of threaded cap screws 85 which extend through cooperatively threaded openings in the stationary bar 79 in abutting relation to the outer side edge of the movable bars 82. Thus, by tightening the adjusting screws 85, the movable clamp bars 82 are caused to move inwardly against the resilient action of the return springs 84, and into clamping engagement with an edge of the plywood die or punch-supporting block 70b, in a manner to tightly clamp the same in connection with the relatively stationary locating keys 75.

The lower shoe section of the die set disclosed in FIGS. 7 through 10 is shown particularly in FIG. 8 of the drawings and is substantially identical in functional construction to the lower shoe section of the first form of die set disclosed in FIGS. 1 through 6 of the drawings, with the exception that the V and fiat locating bosses 34a and 35a are offset with respect to two corners of the lower die or punch-supporting plate members 86 so as to engage the outer concentric surfaces of the bushings 72 at the outer forward side of the die set. Also, in the modified form of the present invention as disclosed in FIGS. 7l0, due to the relatively large size of the upper and lower shoe sections of the die set, it is necessary to employ a plurality of the temporary spring clamps 39a located at spaced intervals along the forward edge of the lower shoe member 73.

It will be apparent that the mode of operation and mechanical principles involved in the modified form of die set disclosed in FIGS. 7-10 of the drawings are identical to that disclosed in FIGS. 1 through 6, in that the punch or die-carrying plates or blocks associated respectively with the upper and lower shoe sections of the die set are always located at a given single position when interchanged between duplicative die sets, this being made possible due to the locating means of both the upper and lower shoe sections being indexed and arranged in given angular and distance relation to the axes of the pin and bushing members.

In view of the foregoing, it will be seen that the present invention provides a novel and improved die set construction characterized by its ability to interchangeably receive and support a cooperative set of punch and die-supporting members in predetermined accurate closing alignment without resort to laborious and expensive prealignment and attachment procedures. Die sets formed in accordance with the present invention make possible the storage and shipment of only the relatively light-weight die and punch-supporting blocks or plates independently of the relatively heavy and large shoe members of the die set. Thus, assuming that two or more die sets of a given size and configuration, formed in accordance with the present invention, are disposed at different locations, a given set of punch and die members may be interchanged between such die sets with a minimum of costs and labor and 10 without resort to the usual prealignment and attachment procedures.

While preferred embodiments of the present invention have been disclosed and described in detail, it will be understood that various modifications as to details of construction and design may be resorted to without departing from the spirit of the invention or the scope of the following claims.

Having thus described this invention, What is claimed 1. A die set comprising a pair of plate-like shoes adapted for connection with relatively reciprocal members of a press; at least two relatively spaced apart, telescoping pin and bushing guide assemblies connecting said shoes for guided, relative, reciprocating movement toward and from one another; punch-supporting means; abutment means carried by one of said shoes in fixed relation to said guide assemblies and against which said punchsupporting means may be positioned to locate the latter in a single given position with respect to said guide assemblies; releasable clamp means carried by said lastnamed shoe for holding said punch-supporting means in said single given position; die-supporting means; indexing means carried by said die-supporting means and including a plurality of relatively spaced, angularly related abutment surfaces engageable with at least two of said guide assemblies for locating said die-supporting means on the other of said shoes in a single given position relative to said guide assemblies, the abutment surfaces of said indexing means including a first surface engaged with one of the guide assemblies and second and third surfaces engaged with two relatively spaced, angularly related surfaces of another of said guide assemblies to prevent lateral movement of said die-supporting means on said other shoes; and releasable fastening means for securing said die-supporting means in said single given position on said other shoe, said die-supporting means and said indexing means being removable as a unit from said other shoe upon release of said fastening means Without changing the positional arrangement of said guide assemblies with respect to said shoes, said first-named abutment means and said indexing means providing means by which said punch-supporting means and said die-supporting means may be accurately located on said shoes in operative relation to one another without resort to trial and error closing of said shoes or the use of supplemental gauging apparatus, thereby providing for interchangeability of said punch-supporting and die-supporting means between duplicative die sets.

2. A die set as defined in claim 1, wherein said die-supporting means comprises at least one rectangular plate member, and said indexing means comprises three triangularly related abutment surfaces projecting outwardly from one edge of said plate member, one of the abutment surfaces of said indexing means being engaged with a surface on the bushing of one of said guide assemblies and the other two abutment surfaces of said indexing means being engaged with two circumferentially spaced surfaces on the bushing of another of said guide assemblies.

3. A die set as defined in claim 1, wherein said punchsupporting means comprises a plywood block having at least two angularly related edge surfaces, and said firstnamed abutment means comprises at least two surfaces disposed in the same angular relation to one another as the said edge surfaces of said block and at fixed, predetermined distances from said guide assemblies.

4. A die set as defined in claim 3, wherein said block is of generally fiat, rectangular configuration, and said first-named abutment means comprises a pair of perpendicularly related rectangular surfaces defining on said one shoe an entrant corner to receive a corner portion of said block, the perpendicularly related rectangular surfaces of said first-named abutment means serving to prevent movement of said block in two directions on said shoe.

5. A die set comprising a pair of relatively thick, platelike shoes; at least two relatively spaced apart sets of rel atively telescoping pin and bushing members connecting said shoes for guided, reciprocating movement toward and from one another; first and second die and punch-supporting means; locating means carried by one of said shoes and defining thereon at least two angularly related abutment surfaces against which one of said supporting means may be positioned to locate the latter at a single given position on said one shoe; means carried by said one shoe for releasably holding said last-named supporting means in said single given position therein; indexing means carried by the other of said supporting means and engaged with the bushings of at least two of said sets of pin and bushing members for locating said other of said supporting means in a single given position on the other of said shoes, said indexing means including three relatively spaced, angularly related, flat surfaces, one of which surfaces is engaged with one surface on the bushing of one set of pin and bushing members and the other two of which surfaces are engaged with two circumferentially spaced surfaces on the bushing of another set of pin and bushing members, whereby to prevent lateral displacement of said other supporting means on the other of said shoes; and releasable fastening means carried by said other shoe for securing said other of said supporting means in said single given position thereon, said die and punch-supporting means and said indexing means being detachable as units from said shoes without disturbing the relative positional arrangement of said sets of pin and bushing members.

6. A die set as defined in claim 5, wherein said other of said supporting means comprises a pair of superposed, detachably connected plate members of different thick nesses, the thinner of said plate members being adapted to directly support thereon a punch or die element, and wherein said indexing means is carried by and projects outwardly from an edge of the thicker of said plate members.

References Cited in the file of this patent UNITED STATES PATENTS 636,913 Mergenthaler Nov. 14, 1899 1,447,247 Hilsdorf Mar. 6, 1923 1,801,490 Falstrorn Apr. 21, 1931 1,954,708 Mass Apr. 10, 1934 2,163,229 Knebel June 20, 1939 2,275,706 Wales Mar. 10, 1942 2,364,401 Stellin Dec. 5, 1944 2,379,271 Bechtel June 26, 1945 2,381,062 Kirsch Aug. 7, 1945 2,545,560 Scott Mar. 20, 1951 2,850,096 Berlin Sept. 2, 1958 FOREIGN PATENTS 566,272 Great Britain Dec. 20, 1944 

